Use of an earpiece acoustic opening as a microphone port for beamforming applications

ABSTRACT

A mobile multi-function device that includes a speaker, two or more microphones, and a beamformer processor is described. The beamformer processor uses the microphones to perform beamforming operations. One of the microphones shares a receiver acoustic opening with the speaker while the other microphone uses a separate acoustic opening. The receiver acoustic opening may be an earpiece opening that is held to the ear of a user while conducting a phone call with the device and provides acoustic input and output paths for the microphone and the speaker, respectively.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of the earlier filing date ofprovisional Application No. 61/698,907, filed Sep. 10, 2012.

FIELD

An embodiment relates to a mobile multi-function device that includes afirst microphone and a receiver speaker that use the same acousticopening for acoustic input and output. The first microphone is usedalong with a second microphone for beamforming applications. Otherembodiments are also described.

BACKGROUND

Mobile multi-function devices often include multiple microphones. Themicrophones may be used for a variety of functions, including placingphone calls and receiving voice commands. The use of multiplemicrophones may allow for a user or target audio source to be clearlyheard when located in a variety of locations relative to the mobilemulti-function device. For example, separate microphones may be locatedon the back and the front of the device such that audio in front or inback of the device may be clearly sensed by a respective microphone.

Although multiple microphones are useful, each microphone requires aseparate hole or acoustic opening in the housing of the mobilemulti-function device such that the microphones are exposed to theoutside environment and allow the microphones to pick-up correspondingsounds. However, although multiple microphones are useful, forming a newopening in the housing for each microphone is aesthetically unappealingand adds additional complications in the design and construction of thehousing.

SUMMARY

A mobile multi-function device that includes a speaker, two or moremicrophones, and a beamformer processor is described. The beamformerprocessor uses the microphones to perform beamforming operations. One ofthe microphones shares a receiver acoustic opening with the speakerwhile the other microphone uses a separate acoustic opening. Thereceiver acoustic opening may be an earpiece opening that is held to theear of a user while conducting a phone call with the device and providesacoustic input and output paths for the microphone and the speaker,respectively. In this embodiment, the receiver acoustic opening islocated on a top portion of the front face of the device.

Since the speaker and the first microphone share the receiver acousticopening, a dedicated acoustic opening is not needed for the firstmicrophone. The lack of another acoustic opening in the housing of thedevice is both aesthetically pleasing and provides for a lesscomplicated design and manufacturing process. Additionally, by using thereceiver acoustic opening, which is located on a top portion of thedevice, the microphone will be unobstructed by the hand of a user whileperforming video conferencing, voice dictation, voice activation, orsimilar operations in which the user is speaking while holding thedevice away from his face

The above summary does not include an exhaustive list of all aspects ofthe present invention. It is contemplated that the invention includesall systems and methods that can be practiced from all suitablecombinations of the various aspects summarized above, as well as thosedisclosed in the Detailed Description below and particularly pointed outin the claims filed with the application. Such combinations haveparticular advantages not specifically recited in the above summary.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the invention are illustrated by way of example andnot by way of limitation in the figures of the accompanying drawings inwhich like references indicate similar elements. It should be noted thatreferences to “an” or “one” embodiment of the invention in thisdisclosure are not necessarily to the same embodiment, and they mean atleast one.

FIG. 1 shows a human user holding a mobile multi-function device, namelya smart phone.

FIG. 2 is a block diagram of the constituent functional unit blocks andhardware components in an example mobile multi-function device withthree microphones.

FIG. 3A is a view of the front face of the device while the device isrunning a video conferencing application.

FIG. 3B is a view of the rear face of the device.

DETAILED DESCRIPTION

Several embodiments are described with reference to the appendeddrawings are now explained. While numerous details are set forth, it isunderstood that some embodiments of the invention may be practicedwithout these details. In other instances, well-known circuits,structures, and techniques have not been shown in detail so as not toobscure the understanding of this description.

FIG. 1 shows a mobile multi-function device 1 (also referred to here asa mobile communications device or a mobile multi-function communicationsdevice) held in the hands of an end user (owner) of the device 1. Themobile multi-function device 1 is a portable, personal apparatus thatmay be held in the hand and carried by a user during operation. In oneinstance, the device 1 is a smart phone or a cellular phone with severalfeatures typically available in modern wireless communication devices,such as a touch screen interface, music, video file recording, playback,digital camera, voice dictation/commands, and wireless-enabledapplications such as voice over internet protocol telephony, videoconferencing, electronic calendar, web browser, and email. In anotherinstance, the device 1 may be a larger, tablet-like computer such as aniPad™ device or a laptop notebook such as a MacBook™ device by AppleInc.

FIG. 2 shows a functional unit block diagram and some constituenthardware components of the mobile multi-function device 1, e.g. as foundin an iPhone™ device by Apple Inc. The device 1 has a housing 2 in whichthe primary mechanism for visual and tactile interaction with its useris a touch sensitive display screen (referred to here as a touch screen)3. The housing 2 may be essentially a solid volume referred to as candybar or chocolate bar type as in the iPhone™ device. An alternative isone that has a moveable, multi-piece housing 2, such as a clamshelldesign, or one with a sliding, physical keypad as used by other cellularand mobile handset or smart phone manufacturers. The touch screen 3 isused to display typical features of visual voicemail, web browser,email, and digital camera viewfinder, as well as others, and to receiveinput from the user via virtual buttons and touch commands.

For wireless telephony, a baseband processor 4 is included to performspeech coding and decoding functions upon the uplink and downlinksignals, respectively, in accordance with the specifications of a givenprotocol, e.g. cellular GSM, cellular CDMA, wireless VOIP. A cellular RFtransceiver 5 receives the coded uplink signal from the basebandprocessor 4 and up converts it to a carrier band before driving anantenna 6 with it; it receives a downlink signal from the antenna 6 anddown converts the signal to baseband before passing it to the basebandprocessor 4. A wireless local area network transceiver 7 receives andtransmits data packets from a nearby wireless router or access point,using an antenna 8.

Power is provided to operate the components shown in FIG. 2 by a battery9 (generically used here to refer to a rechargeable power source thatmay also include a rechargeable fuel cell). The battery 9 is charged orreplenished by an external power source such as a wall plug orautomobile battery dc power adapter (not shown) that connects to amulti-pin docking connector 10 that is also integrated in the housing 2of the device 1. The connector 10 and its associated charger and I/Ointerface circuitry 11 may be in accordance with any suitable computerperipheral specification such as Universal Serial Bus (USB). The USBprotocol allows for the connector 10 and its associated interface 11 tobe used for both power transfer to recharge the battery 9 and for dataI/O communications. The latter includes docking functions, tosynchronize user content in the device 1 with another computer deviceowned by the user that may have substantially more data storagecapacity, e.g. a desktop computer, a laptop/notebook computer.

The mobile multi-function device 1 may include a power management unit(PMU) 12. The PMU 12 is typically implemented as a programmed processor,with associated analog and digital conversion circuitry, analog signalconditioning circuitry, and a data communications interface needed tocontrol or communicate with other components of the device 1 (forpurposes of thermal management). The PMU 12 obtains temperature data (ortemperature readings) from multiple temperature sensors 13, and thenprocesses that data to make decisions that affect power consumptionactivity, in order to maintain specified thermal levels for the device1. The PMU 12 may include power supply circuitry with various regulatedvoltage outputs for supplying power to the components of the device 1.The PMU 12 may also be tasked with the orderly powering down andpowering up the various components of the device 1, in response tosystem reset or the main power on/off switch being actuated by the user.

The device 1 may also include a motion sensor 14 which may use anaccelerometer to measure linear acceleration of the device 1 along agiven axis. The motion sensor 14 may use a MEMS type mechanical sensoror gyroscope to measure turn rate or angular velocity of the device 1about a given axis.

The device 1 may also include one or more cameras 15 integrated into thehousing 2. The cameras 15 may be any camera type suitable for beingintegrated in a mobile device, including Complementarymetal-oxide-semiconductor (CMOS) cameras. The cameras 15 may beseparately located on front and rear faces of the device 1 andaccordingly directed at respective front and rear areas of the device 1such that a corresponding application running on the device 1 may useone or both of the captured scenes.

The user-level functions of the device 1 are implemented under controlof a processor 16 that has been programmed in accordance withinstructions (code and data) stored in memory 17. The processor 16 andmemory 14 are generically used here to refer to any suitable combinationof programmable data processing components and data storage that conductthe operations needed to implement the various functions of the device1. The processor 16 may be an applications processor typically found ina smart phone, while the memory 17 may refer to microelectronic,non-volatile random access memory. An operating system may be stored inthe memory 17, along with application programs specific to the variousfunctions of the device 1, which are to be run or executed by theprocessor 16 to perform the various functions of the device 1. Forinstance, there may be a telephony application that (when launched,unsuspended, or brought to foreground) enables the user to “dial” atelephone number to initiate a telephone call using a wireless VOIP or acellular protocol and to “hang up” on the call when finished.Additionally, the processor 16 may run other applications, including amultimedia/video call application (such as provided by FaceTime™developed by Apple Inc.), a voice dictation/activation application (suchas provided by Siri™ developed by Apple Inc.), and a video recordingapplication.

The device 1 may include an audio codec 18 for coding or decoding a datastream or signal. The audio codec 18 may receive inputs signals from oneor more microphones 19 and output signals to a speaker 20. Conversionbetween analog domain and digital domain for the speaker and microphonesignals, in addition to digital audio signal processing for differentapplications running on the device 1, may be performed within the audiocodec 18. A physical volume switch or button may also be connected tothe codec 18. The codec 18 may be configured to operate in differentmodes, e.g. to service a digital media player function (such as an MP3player that is playing back a music file that is stored in the device1), as well as a wireless telephony function.

The speaker 20 may be any type of electroacoustic transducer thatproduces sound in response to an electrical audio signal input. Forexample, the speaker 20 may use a lightweight diaphragm, or cone,connected to a rigid basket, or frame, via a flexible suspension thatconstrains a coil of wire (e.g. a voice coil) to move axially through acylindrical magnetic gap. When an electrical audio signal is applied tothe voice coil, a magnetic field is created by the electric current inthe voice coil, making it a variable electromagnet. The coil and thespeaker's 20 magnetic system interact, generating a mechanical forcethat causes the coil (and thus, the attached cone) to move back andforth, thereby reproducing sound under the control of the appliedelectrical audio signal coming from a source, such as the audio codec18. Although described as including a single speaker 20, the device 1may alternatively include multiple speakers 20 driven in a similarfashion as described above.

As shown in FIG. 3A, the speaker 20 uses a first acoustic opening 21 asan acoustic path or output port to expose the speaker 20 to the areasurrounding the device 1. The first acoustic opening 21 is located on anupper portion of a front face or surface 24 of the device 1. As usedherein in, the front face 24 is the side the device 1 that includesaccess for the user to the touch screen 3. The first acoustic opening 21may be a receiver or earpiece opening that is held to the ear of a userwhile conducting a phone call with the device 1. The first acousticopening 21 may be a slot or a hole in the housing 2 that allows soundproduced by the speaker 20 to emanate into a room or into the ear canalof a user. As shown in FIG. 3A, the first acoustic opening 21 iselliptical. In other embodiments, the first acoustic opening 21 may berectangular or formed from a set of small holes. The first acousticopening 21 may be drilled or otherwise formed in the housing 2 duringmanufacturing of the device 1. In one embodiment, the first acousticopening 21 includes a grille or a grating that shields the speaker 20from foreign objects and unduly high pressure that may damage thespeaker 20.

The microphones 19 may be any type of acoustic-to-electric transducer orsensor, including MicroElectrical-Mechanical System (MEMS) microphones,piezoelectric microphones, electret condenser microphones, or dynamicmicrophones. The microphones 19 may be situated in different areas ofthe device 1 as described in more detail below.

In one embodiment, a first microphone 19A is located along a bottom sideof the device 1. The first microphone 19A may be primarily used duringvoice calls to receive audio from a user of the device 1 while the userhas the device 1 up to his ear. The housing 2 may include a secondacoustic opening or hole 22 that the microphone 19A uses as an acousticpath or input port to expose the first microphone 19A to the areasurrounding the device 1. The second acoustic opening may be drilled orotherwise formed in the bottom side of the housing 2 duringmanufacturing of the device 1.

As shown in FIG. 3B, in one embodiment a second microphone 19B islocated along a rear face or surface 25 of the device 1. The secondmicrophone 19B may be used for beamforming operations as will bedescribed in further detail below. The housing 2 may include a thirdacoustic opening 23 or hole that the microphone 19B uses as an acousticpath or input port to expose the second microphone 19B to the areasurrounding the device 1. The third acoustic opening 23 may be drilledor otherwise formed in the housing 2 during manufacturing of the device1.

In one embodiment, a third microphone 19C is located on the front face24 of the housing 2 as shown in FIG. 3A. The third microphone 19C may beused along with the second microphone 19B for beamforming operationsperformed by a beamformer processor 26 as will be described in furtherdetail below.

In one embodiment, the third microphone 19C shares the first acousticopening 21 with the speaker 20 such that the third microphone 19C isexposed to the area surrounding the device 1 through the acoustic pathor port provided by the first acoustic opening 21. In one embodiment,the third microphone 19C is a microphone array with two or moretransducers located in the first acoustic opening 21. Since the thirdmicrophone 19C and the speaker 20 share the first acoustic opening 21, adedicated acoustic opening is not needed for the third microphone 19C inthe housing 2 of the device 1. The lack of another acoustic opening inthe housing 2 is both aesthetically pleasing and provides for a lesscomplicated design and manufacturing process.

Additionally, by being located in the first acoustic opening 21, whichis located on a top portion of the device 1, the microphone 19C will beunobstructed by the hand of a user while performing video conferencing,voice dictation, voice activation, or similar operations in which theuser is speaking while holding the device 1 away from his face. Forexample, during a video conference, as shown in FIG. 3A, a usertypically grips a bottom portion of the device 1 such that the camera 15is framing the user. In this scenario, the user's hand might be blockingthe microphone 19A which is located along the bottom side of the device1, while the microphone 19B is facing away from the user along the rearface 25 of the device 1. However, the third microphone 19C isunobstructed and can pick up the speech from the user.

Turning now to the processing of signals produced by the microphones 19,the beamformer processor 26 will now be described. The beamformerprocessor 26 receives inputs from two or more microphones 19 in thedevice 1 and performs audio beamforming operations. Audio beamforming isa technique in which sounds received from two or more microphones arecombined to enable the preferential capture of sound coming from certaindirections. The beamformer processor 26 may combine the signals capturedby microphone 19B and microphone 19C to generate a single output toisolate a sound from background noise. For example, in delay sumbeamforming each of the microphones 19B and 19C independentlyreceive/sense a sound and convert the sensed sound into correspond soundsignals. The received sound signals are summed to determine the sound'sdirectional angle. The maximum output amplitude is achieved when thesound originates from a source perpendicular to the array. That is, whenthe sound source is perpendicular to the array, the sounds will allarrive at the same time at each of the microphones 19B and 19C and aretherefore highly correlated. However, if the sound source isnon-perpendicular to the array, the sounds will arrive at differenttimes and will therefore be less correlated, which will result in alesser output amplitude. The output amplitude of various sounds makes itpossible to identify background sounds that are arriving from adirection different from the direction of the sound of interest. Basedon the identification of background or noise sounds, the beamformerprocessor 26 performs directed reception of desired sounds. For example,the beamformer processor 26 may use the inputs received from themicrophones 19B and 19C to produce a variety of audio beamformingspatial directivity response patterns, including cardioid,hyper-cardioid, and sub-cardioid patterns. The patterns can be fixed oradapted over time, and may even vary by frequency.

In one embodiment, the beamformer processor 26 is purely implemented asa set of hardware circuits, state machines, digital filter blocks, andprocessors. In another embodiment, the beamformer processor 26 isimplemented in software and run by the main system processor 16 afterbeing accessed from the memory 17. In another embodiment, the beamformerprocessor 26 is implemented using a combination of hardware elements(e.g. hardware circuits, state machines, and digital filter blocks) andsoftware run by the main system processor 16 after being accessed fromthe memory 17.

In one embodiment, the beamformer processor 26 may be used to generate adirectivity pattern to capture sounds along the front face 24 of thedevice 1 during a traditional audio-only call, a multimedia/video call(such as provided by FaceTime™ developed by Apple Inc.) or a voicedictation/activation operation (such as provided by Siri™ developed byApple Inc.). In another embodiment, the beamformer processor 26 may beused to generate a directivity pattern to capture sounds along the rearface 25 of the device 1 during a video capture operation performed usinga camera 15 on the rear face 25 of the device 1.

As explained above, an embodiment of the invention may be amachine-readable medium (such as microelectronic memory) having storedthereon instructions, which program one or more data processingcomponents (generically referred to here as a “processor”) to performbeamforming operations described above. In other embodiments, some ofthese operations might be performed by specific hardware components thatcontain hardwired logic (e.g., dedicated state machines). Thoseoperations might alternatively be performed by any combination ofprogrammed data processing components and fixed hardwired circuitcomponents.

While certain embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative of and not restrictive on the broad invention, andthat the invention is not limited to the specific constructions andarrangements shown and described, since various other modifications mayoccur to those of ordinary skill in the art. The description is thus tobe regarded as illustrative instead of limiting.

What is claimed is:
 1. A mobile device, comprising: a mobilemulti-function phone handset housing that contains: a speaker to producesound for an audio application that is to execute in the mobile device;first, second, and third microphones for capturing audio proximate tothe mobile multi-function phone handset housing; and a beamformerprocessor for performing directional signal reception of audio using thefirst and second microphones in video call mode, where the housing has afirst acoustic opening located on a front face and at a top end of thehousing, and designed to be held to the ear of a user when the device isbeing used like a telephone handset during a phone call, the firstacoustic opening to provide shared acoustic input and output paths forthe first microphone and the speaker, wherein the housing furtherincludes a second acoustic opening located on a rear face of the housingthat is used by the second microphone as an input acoustic port, whereinthe housing further includes a third acoustic opening located on abottom side of the housing that is near the mouth of the user when thedevice is being used like a telephone handset during the phone call,wherein the third acoustic opening is used by the third microphone as aninput acoustic port.
 2. The mobile device of claim 1, wherein the firstacoustic opening is an ear piece receiver opening.
 3. The mobile deviceof claim 1, wherein the beamformer processor generates a reception beamdirected at an area along the front face of the mobile device while themobile device is in video call mode.
 4. The mobile device of claim 1,wherein the beamformer processor generates a reception beam directed atan area along the rear face of the mobile device.
 5. A method foroperating a mobile multi-function device, comprising: running anapplication on the mobile multi-function device, wherein the mobilemulti-function device includes a first microphone and a speaker locatedin a first acoustic opening on a front face and top end of the mobilemulti-function device such that the first acoustic opening is designedto be held to an ear of a user during a phone call, wherein the mobilemulti-function device includes a second microphone located in a secondacoustic opening on a rear face of the mobile multi-function device, andwherein the mobile multi-function device further includes a thirdmicrophone located in a third acoustic opening on a bottom side of themobile multi-function device; and performing beamforming operationsduring a video conference call using the first microphone installed inthe first acoustic opening of the mobile multi-function device and thesecond microphone installed in the second acoustic opening.
 6. Themethod of claim 5, wherein the first opening is an ear piece receiveropening.
 7. The method of claim 5, wherein performing the beamformingoperations includes generating a reception beam directed at an areaalong the front face of the device during the video conference callperformed by the mobile multi-function device.
 8. A method forconstructing a mobile multi-function device, comprising: forming aspeaker opening on a front face and top end of a housing of the mobilemulti-function device; installing a first microphone and a speaker touse the speaker opening as an acoustic input and output port; forming afirst microphone opening on a rear face of the housing of the mobilemulti-function device; installing a second microphone to use the firstmicrophone opening as an acoustic input port; forming a secondmicrophone opening on a bottom side of the housing of the mobilemulti-function device; installing a third microphone to use the secondmicrophone opening as an acoustic input port and configuring abeamformer processor in the mobile multi-function device to performdirectional signal reception of sound using the first and secondmicrophones while in video call mode.
 9. The method of claim 8, whereinthe speaker opening is an ear piece receiver opening designed to be heldto the ear of a user during a phone call.
 10. The method of claim 8,wherein the beamformer processor is configured to generate a receptionbeam directed at an area along the front face of the device during avideo conference call performed by the mobile multi-function device.